The goal of this project is to assess the feasibility of a new, unique, simplified total artificial heart (TAH) design, which is comprised of a single pump assembly with two impellers and one motor. This approach uses novel continuous flow pump design features to balance atrial pressures (and hence flows), thereby facilitating self balancing. This double pump concept includes a single continuously rotating brushless DC motor and pump assembly with a centrifugal pump on both ends. Both pumps are on the same shaft, and therefore rotate at the same speed. Such a design would dramatically reduce the size and complexity of the TAH compared to the devices currently implanted clinically. The system would require only a single three-conductor percutaneous power cable and a single sensorless controller. The overall result would be a TAH that could be implanted into smaller patients with a potentially reduced risk for device failure and morbidity. [unreadable] [unreadable] A critical issue is to optimize the self balancing of right and left pump flows so that the right and left impellers can be operated at the same speed and still maintain acceptable atrial pressure balance over a wide range of vascular resistances. In the current working model, the rotating assembly moves axially in response to hydraulic forces to open and close an aperture at the outside diameter of the right impeller, thereby automatically changing the relative left/right performance. The proposed physiologic speed control algorithm is based upon characteristic relationships between flow and SVR and functions of speed and power. Pulsatility is created via cyclic motor power modulation. The pump's speed response to that current pulse will be analyzed to obtain indications of atrial suction to indicate the need to reduce pump speed. [unreadable] The following Specific Aims will allow a determination of the feasibility of this unique concept [unreadable] 1) Develop a computer model of the pump coupled to the circulatory system in which pump components and hemodynamic parameters are programmable variables. [unreadable] 2) 2) Design, fabricate, and in vitro test two pump versions based upon the computer system model resulting from Specific Aim #1. [unreadable] 3) 3) In vitro evaluation of self balancing flow and physiologic speed control. [unreadable] 4) 4) Acute in vivo hemodynamic evaluation [unreadable] PUBLIC HEALTH RELEVANCE: Existing total artificial hearts (TAH) are either externalized and temporary or implantable with significant limitations due to size and durability. These devices also do not lend themselves to greater reductions in size due to the inherent characteristics of the design technology. The Continuous Flow Total Artificial Heart's revolutionary design would allow the device to be dramatically reduced in size and complexity allowing implantation into smaller patients with a potentially reduced risk for device failure and morbidity. [unreadable] [unreadable] [unreadable]